The invention concerns an operating mechanism for a tiltable sliding cover of a roof of a motor vehicle having an electric motor by means of which the sliding cover can be operated by a transmission, at least one threaded cable and a cover-adjusting unit connected with the threaded cable and having a switching arrangement that is in operating connection with the cover-adjusting unit and is rendered operative as a function of the position of the cover-adjusting unit, with said switching arrangement having the purpose of switching off the current supply to the electric motor in the position of the cover-adjusting unit that corresponds to the closed position of the sliding cover.
An operating mechanism of this type was described in commonly-assigned U.S. patent application Ser. No. 291,055, filed Aug. 7, 1981. For a perfect functioning of such a mechanism, it is important that the response of the switching arrangement be synchronized precisely with the adjusting movement of the sliding cover so that the cover, starting from a pushed-back position or a tilted-out position, is arrested precisely in the closed position. Because of the unavoidable tolerances, this synchronization must be carried out for each individual motor vehicle. In the case of the previous patent application mentioned above, this was achieved by the fact that, first the cover-adjusting unit and the cover are installed in the motor vehicle and are manually pushed into a predetermined position before the unit, consisting of the electric motor, the transmission and the switching arrangement, is brought into operating connection with the cover-adjusting unit when the switching arrangement is in a specified position.
The present invention has, as an object, the creation of an operating mechanism that can be installed more rapidly and more easily.
Using an operating mechanism of the initially mentioned type as a starting point, the noted object of the invention is achieved, in accordance with a preferred embodiment, by providing, between the cover-adjusting unit and the switching arrangement, a clutch by means of which the operating connection between the cover-adjusting unit and the switching arrangement can be interrupted.
The development according to the present invention makes it possible to install the cover-adjusting unit with the threaded cable or cables and the motor with the transmission, as well as the switching arrangement, being in the predetermined position, when the clutch is disengaged. The cover-adjusting unit may then, if desired, together with the sliding cover, by means of the motor, be brought into a predetermined position, expediently into the fully tilted position. As soon as the cover-adjusting unit takes up this predetermined position, the clutch is engaged in order to establish the operating connection between the cover-adjusting unit and the switching arrangement that is adjusted to this predetermined position. Said construction significantly simplifies the installation. The operational parts required for the adjustment of the cover can be largely premounted and preadjusted before they are installed into the motor vehicle at the production line and can be coupled with one another by a few simple manipulations in a precisely synchronized manner.
In order to avoid an accidental shifting of the adjusted switching arrangement when the clutch is disengaged, a blocking means is provided, as a further aspect of the invention, for blocking the switching arrangement when the operating connection, between the cover-adjusting unit and the switching arrangement, is interrupted by means of the clutch. For the purpose of an especially simple construction, the clutch and the blocking means may expediently be combined into one structural unit.
The operating drive of the switching arrangement is preferably transmitted by the threaded cable by means of a pinion, which, together with the threaded cable, forms the clutch. This pinion is expediently mounted on a pinion shaft which can be moved axially between a first axial position, in which the pinion is disengaged from the threaded cable, and a second axial position, in which the pinion is engaged with the threaded cable. In this manner, structural elements are used for the clutch which cause no significant additional expenses. In this case, a shape-keyed mating element can be provided as the blocking means which sits on the pinion shaft and which, when the pinion shaft is in the first axial position and in the predetermined angular position, is in mating connection with an opposing element attached to the housing, and which, in the second axial position of the pinion shaft, is disengaged from the opposing element. In this manner, the blocking means also can be constructed simply, reliably and cost-effectively.
The switching arrangement expediently has a step-by-step gear-shift consisting of a ratchet wheel that is connected with the pinion shaft in a manner fixed against relative rotation in both axial positions, and a stop wheel by means of which a contact arm of a limit switch can be activated that controls the current supply to the electric motor.
The mating element of the pinion shaft expediently consists simply of one or several adjacent teeth, and the opposing element in such a case is an internal toothing that is attached to the housing, with the internal toothing extending over a larger curvature area than the mating element of the pinion shaft. In order to be able to easily adjust the pinion shaft, the pinion shaft, preferably on one of its front sides, has a radial slot into which an appropriate tool, for example, a screwdriver, can be inserted. In this case, preferably a part of the housing that houses the pinion shaft, in the area of the slotted end of the pinion shaft, has one or more radial slots aligned with the axis of the pinion shaft. In combination with the radial slot of the pinion shaft, these radial slots may be used as markings for adjusting purposes.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.